Consider the tang as cheese for your sandwich. Make it suit your bread size.
Before you cut, make sure where you are planning your tang bolt to be located. You want that bolt to land ahead of the trigger(s).
Tangs are usually supplied long, so the customer can trim to their project. Some tangs are ridiculously wide, so you can shape the sides down, too, if your gun calls for it.
Here is one of mine, and the tang bolt hits the trigger plate comfortably ahead of the double set triggers.